Area Forecast Discussion
Issued by NWS Upton, NY

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FXUS61 KOKX 201959

Area Forecast Discussion
National Weather Service New York NY
359 PM EDT Thu Oct 20 2016

A warm front will slowly approach from the south tonight. A cold
front will move through late Friday with showers likely. Deepening
low pressure tracks across New England Friday night into Saturday.
This low pressure will spin over Quebec this weekend. A cold
frontal passage will occur Monday, allowing high pressure to
build into the region through the middle of the week.


Stratus has moved in from the south. Persistent E/SE flow to the
north of the warm front continues overnight. Amplifying trough
approaches from the west.

Generally expect low clouds to persist through the overnight
hours. Spotty light rain or drizzle is possible, along with the
development of fog. Analysis of NWP and high resolution models
does not suggest any organized area of rain other than the
aforementioned spotty light rain/drizzle. However, as moisture
gets pulled northward ahead of the sub tropical low, a few showers
could develop later tonight.

With the clouds and easterly wind flow, temperatures tonight
should be fairly uniform for this time of year, with lows ranging
from the mild lower to mid 60s near the coast, to the mid and
upper 50s inland.


Amplifying trough tracks east as it becomes negatively tilted, and
cuts off Friday night.

At the surface, frontal boundary and wave of low pressure tracks
east across the area by afternoon. Low pressure over the Atlantic
lifts northward, passing to the east. A warm front also tracks
northward ahead of the frontal boundary. The front moves slowly
east of the area Friday night as surface low develops across
eastern New England and deepens.

Coverage of showers remains in question, and axis of heavier rain
is in doubt. However, latest 12Z model suite does look drier

Marginal Capes could be enough for isolated thunder Friday
afternoon as lift increases ahead of the trough.

Temperatures will be warm, in the lower to mid 70s during the day,
falling into the 50s at night. They could be lower depending on
speed of the front, and any cooler air ushering in late at night.


Windy and cooler weather can be expected this weekend as low
pressure deepens over New England and Quebec on Saturday, then
drifts towards Labrador Sunday night. The GFS, GEM and ECMWF are all
very similar with the evolution of the system, suggesting a 500
millibar closed low develops over central Pennsylvania Friday night,
tracks into upstate New York on Saturday, and then north of Quebec
City on Sunday.

For Saturday, the synoptic lift will be exiting the region.
However, very steep low level lapse rates will develop. In fact,
the GFS progs superadiabatic lapse rates in the approximately
15-21Z time period. This should result in at least broken cloud
cover and scattered showers. Across the northern tier, their may
be enough moisture to result in greater coverage and perhaps some
periods of steady rain. This precipitation will have to overcome
the downslope however on top of the synoptic subsidence, so
limited the rain to scattered showers.

Because of the expected cloud cover, this should help to temper
wind gusts a bit. As a result, wind gusts were capped at around
40 mph. This is essentially full mixing from 950 millibars in the
GFS. The best chance at this time for over-performing winds
reaching advisory criteria looks to be Saturday morning as the
pressure rapidly rises.

The precipitation winds down Saturday night as the low and
associated moisture gets too far away, but the gusty winds will
continue right through Sunday with the low still in the 980s over

A clipper type system will be racing towards the forecast area on
Monday. This will allow winds to back to the southwest and may allow
a quick warm up if the cold frontal passage is slow enough. The
12Z data however has the front coming through during the early
afternoon at the latest, so high temperatures close to those
expected on Sunday were forecast.

The airmass that builds in for the Tuesday and Wednesday time period
looks to be around 10 degrees below average, and will have the
potential to produce a freeze across much if not all of the
interior, possibly getting into some of the coastal zones.

A frontal system of Pacific origin may reach the area on Thursday
per the ECMWF. A slower timing is preferred for this type of a
system this far out however, so precipitation chances were
limited to slight chance.


A warm front to the south will move northward towards the area
into this evening, and gradually pass north overnight.

MVFR conditions will continue into the evening. Good model agreement
with visibility and ceilings leading to a period of LIFR conditions
for all TAF sites starting around 06z. Keeping drizzle in the
forecast for the overnight ahead of the warm front. Expecting
temporary improvement in conditions towards mid-morning on Friday,
before a possible return to IFR/LIFR conditions during the day
tomorrow in any developing showers.

Easterly winds expecting to remain gusty ahead of the front, and
diminish this evening after the loss of daytime heating and as the
gradient relaxes.

     NY Metro Enhanced Aviation Weather Support...

Detailed information, including hourly TAF wind component forecasts,
can be found at: http:/

KJFK TAF Comments: Gusty easterly winds diminishing this evening.
LIFR conditions may develop earlier than forecast.

KLGA TAF Comments: LIFR conditions may develop earlier than

KEWR TAF Comments: LIFR conditions may develop earlier than forecast.

KTEB TAF Comments: LIFR conditions may develop earlier than forecast.

KHPN TAF Comments: Gusty easterly winds diminishing this evening.
LIFR conditions may develop earlier than forecast.

KISP TAF Comments: LIFR conditions may develop earlier than forecast.

.Outlook for 18Z Friday through Tuesday...
.18Z FRI...Showers with MVFR or lower conditions likely. NW winds
G30-35KT developing late Friday night.
.SAT... NW winds G30-35KT. Chance of MVFR early.
.SAT NIGHT...Mainly VFR. W winds G25KT.
.SUN...VFR. W winds G30KT.
.SUN NIGHT...Mainly VFR. W winds G20KT.
.MON...Mainly VFR. W winds G20KT in the afternoon.
.TUE...Mainly VFR. NW winds G20KT.


Will maintain SCA on the eastern waters into this evening as seas
remain around 5 ft, and east winds continue to gust close to 25
kt. As the night progresses, winds diminish, and seas subside.

A frontal boundary slowly moves across the waters Friday, as winds
eventually turn toward the south. Expect a wind shift Friday
night, generally after midnight, to the west.

Seas doe build over the ocean Friday night, and a few gusts could
approach 25 kts late at night. Will issue a SCA for the two
western waters as a result.

Gales are possible over the weekend as deep low pressure spins north
of the waters. A watch has been issued for Saturday and Saturday
night, but they may extend into Sunday. A cold frontal passage on
Monday will have the potential to produce small craft advisory
conditions though Tuesday, especially on the ocean where seas are
likely to at least remain in the 3 to 5 ft range.


Rainfall tonight should be light in spotty light rain or drizzle.

Showers are possible Friday and Friday night. Totals should
average around 1/2 an inch. No hydrologic problems are expected.

Less than a quarter of an inch of precipitation is expected over the
weekend. Mainly dry weather is expected thereafter.


As high tide passes this afternoon, no additional coastal flooding
is anticipated. It appears that tide levels remained just below

The potential also remains for minor coastal flooding ahead of an
approaching frontal system with the Fri afternoon high tide cycles.
Generally 1-2 ft departures are needed for minor flooding.


MARINE...Gale Watch from Saturday morning through late Saturday night
     for ANZ330-335-338-340-345-350-353-355.
     Small Craft Advisory from 6 PM Friday to 6 AM EDT Saturday for
     Small Craft Advisory until midnight EDT tonight for ANZ350.


TIDES/COASTAL FLOODING...PW is the U.S. government's official web portal to all federal, state and local government web resources and services.